Aerial dancers at City Hall, a choreographed dance performance in the water and a Latin jazz duo help mark the opening of Grand Park's final section.

Owen Williams, 7, and his sister Brooke, 3, play in the Arthur J. Will Memorial… (Wally Skalij, Los Angeles…)

Thousands of people gathered in the new Grand Park on Saturday to watch aerial dancers scale City Hall, performers splash in the fountain and other festivities marking the opening of downtown Los Angeles' major new green space.

The rectangular park, which stretches from the top of Bunker Hill to the base of City Hall, has been partially open since midsummer. The opening of the lower section completes the project, which includes lawns, fountains and a cafe plaza.

The project has been billed as L.A.'s Central Park, and officials hope it will blossom into a cultural hub. But for some visitors Saturday, it was enough just to have a new urban retreat.

"It's wonderful that you can have 12 acres of beauty in the heart of a metropolis," said Bob Moore, 64, of Shadow Hills.

Judy Fierro, 49, has already incorporated the park into her daily routine. She and her co-workers climb the stairs for a midday workout. And every Wednesday, she has an early morning coffee break with her husband on one of the bright pink chairs. "We think this park is just grand," Fierro said.

With its massive water fountain and a wading pool, the park has become an attraction for youngsters looking to cool off during recent hot spells.

"I'm glad to see that L.A. has a world-class park," said Kirby Pringle, 40, of Los Feliz, as he readied his sons, 7 and 5, to play in the water.

Pringle takes his boys and his 1-year-old daughter on the Metro Red Line twice a week to get to the "oasis in downtown," he said.

The festivities kicked off with a choreographed dance performance in the water. Later, Latin jazz duo Dos y Mas played as families and couples sat on the lawn. Los Angeles County Supervisor Gloria Molina and other guests spoke against the backdrop of City Hall.

The event closed with the aerial dance group Bandaloop suspended from ropes hundreds of feet above Grand Park.

For some, it was their first visit. Cyndy Jhueng works nearby but heard about Grand Park only after friends asked to meet up there. "I'm surprised by how nice it is," said Jhueng, 33.